1. Field of the Invention
The present invention relates to a crystal production method.
2. Description of Related Art
Conventionally, as the crystal production method, there is known a method in which a melt of raw materials for a single crystal to be fabricated is prepared, and the melt is precipitated on a single crystal serving as a seed. However, it has been difficult to apply this method to materials which have a very high melting point or which are apt to be decomposed, such as high-melting-point oxides, e.g., ZnO, nitrides (e.g., GaN), and carbides (e.g., SiC). Accordingly, for example, regarding GaN, a Na-flux method has been proposed in which raw materials are melted, using Na as a flux, and precipitated on a seed to obtain a single crystal (for example, refer to Patent Document 1). Furthermore, a method has been proposed in which a GaN phase is formed using hydride vapor phase epitaxy on a heterogeneous substrate, such as sapphire, and after the growth of the GaN phase, the heterogeneous substrate is removed, thereby to obtain a self-supporting, GaN single crystal substrate (for example, refer to Patent Document 2). Furthermore, an aerosol deposition process has been proposed in which by spraying an aerosol of a raw material powder onto a single-crystal substrate, a film containing a raw material component is formed on the substrate, and then by performing heat treatment, a single crystal is grown (for example, refer to Patent Document 3).    Patent Document 1: U.S. Pat. No. 5,868,837    Patent Document 2: JP 2003-178984 A    Patent Document 3: JP 2006-298747 A